Field of the Invention
The invention relates to a supporting or guiding device for sheets in a sheet processing machine, particularly a printing press.
It has become known heretofore to provide pneumatically actuatable guide elements for producing an air cushion between respective sheets and guide elements, for contact-free transport of sheets in printing presses. Such an air cushion prevents the respective sheets from coming into contact with the guide elements.
There are a great number of regions in the printing press wherein pneumatically actuated guiding devices are employed. Such regions are, for example supporting rods for sheets or sheet piles in the feeder or delivery, the upper side of the pregripper, separator shoes, guide elements in the pocket or wedge region of cylinders, smoothing and decurling devices, guide elements on the circumference of cylinders of the reversing or turning device or on the circumference of sheet transport cylinders, and so forth.
A method of generating throttled blast or blown air for supporting bodies is known from International Application No. WO 01/14752 A1, which corresponds to U.S. Pat. No. 6,523,572. In that method, a throttling or restricting segment or distance is provided between a blast or blown air outlet and a blast or blown air inlet. Therefore, a passageway for blast or blown air is formed in a plane between an outlet surface and a cover surface. The passageway has outer walls whereon ribs are disposed for producing swirling of the blast or blown air.
Such throttling or restricting segmentes or distances, however, can be produced only with a great deal of expenditure. Therefore, the cost/benefit ratio is economically disadvantageous.
German Patent DE 44 06 739 C2, which corresponds to U.S. Pat. No. 5,505,124, discloses the production of throttled negative pressure or vacuum for holding a flat element. In that regard, a throttle segment or distance for suction air is formed between a supporting surface facing towards the flat element and a throttling surface located at a distance therefrom. That is done by placing intermediate layers on top of one another, with apertures formed in the layers. In that regard, a plurality of small apertures in one intermediate layer are brought into coincidence with a respectively large aperture formed in another intermediate layer. In that configuration, a plurality of inlet openings are connected simultaneously to a plurality of outlet openings.
It is accordingly an object of the invention to provide a supporting or guiding device for bearing or guiding sheets in a sheet processing machine, in particular a printing press, which overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices of this general type and with which throttled blast or blown air is made available.
With the foregoing and other objects in view, there is provided, in accordance with the invention, a supporting or guiding device for sheets in a sheet processing machine. The device comprises a first layer having a supporting or guiding surface formed with a plurality of outlet openings for applying a throttled air flow therethrough to a respective sheet. A covering plate is spaced away from the supporting or guiding surface. At least two intermediate layers, respectively formed with a plurality of openings, are disposed between the supporting or guiding surface and the covering plate. The covering plate is connected via a plurality of inlet openings to at least one blast air source. A respective opening formed in one of the intermediate layers is connected to two respective openings formed in the other of the intermediate layers, and an opening formed in the other intermediate layer is connected to two respective openings formed in the one intermediate layer, between one of the respective inlet openings and one of the respective outlet openings associated therewith.
In accordance with another feature of the invention, the supporting or guiding device further includes a further layer disposed between the one intermediate layer and the other intermediate layer.
In accordance with a further feature of the invention, the further layer is formed with openings disposed in a region of a throttle segment located between the respective inlet opening and the respective outlet opening.
In accordance with an added feature of the invention, the supporting or guiding device further includes yet a further intermediate layer, respectively disposed between the supporting and guiding surface and the one intermediate layer, and between the covering and the other intermediate layer.
In accordance with an additional feature of the invention, the further intermediate layers are respectively formed with openings disposed in a region of the throttle segment.
In accordance with yet another feature of the invention, in addition to the intermediate layers, there is provided a relatively large plurality of further intermediate layers.
With the objects of the invention in view, there is also provided a supporting or guiding device for sheets in a sheet processing machine. The device comprises a first layer having a supporting or guiding surface formed with a plurality of outlet openings for applying a throttled air flow therethrough to a respective sheet. A covering plate is spaced away from the supporting or guiding surface. At least two intermediate layers, respectively formed with a plurality of openings, are disposed between the supporting or guiding surface and the covering plate. The covering plate is connected via a plurality of inlet openings to at least one blast air source. A further layer is disposed between the at least two intermediate layers, between the respective inlet opening and the respective outlet opening associated therewith. The openings formed in one of the at least two intermediate layers is located opposite the openings formed in the other of the at least two intermediate layers, and respective lands between respective openings formed in the one intermediate layer are disposed opposite respective lands formed in the other intermediate layer.
In accordance with a further feature of the invention, the further layer has a greater thickness than the at least two intermediate layers.
In accordance with an added feature of the invention, the further layer is formed with openings respectively disposed in a region of the lands of the one intermediate layer and the lands of the other intermediate layer.
In accordance with an additional feature of the invention, the further layer is formed with openings having a smaller passthrough than the openings formed in the intermediate layers.
In accordance with a concomitant feature of the invention, the sheet processing machine is a printing press.
An advantage of the invention is, for one, the low overall height of the guiding or supporting device, and the cost-effective capability of producing the same. This is because the throttle segment can be formed simply of sheetmetal provided with a plurality of openings or apertures, which can be produced cost-effectively by simple punching or stamping.
It is furthermore beneficial, for example, to provide different paths for the blast or blown air within a throttle segment or section due to the disposition of a plurality of layers.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a supporting or guiding device for sheets in a sheet processing machine, in particular a printing press, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.